1. Field of the Invention
The present invention relates to a method of monitoring the sound within a car, and more particularly, to a method of monitoring the sound within a car at a place remote from the car by utilizing a mobile telephone system.
2. Description of the Prior Art
Anti-theft devices which prevent auto theft are conventionally known. When a thief attempts to steal a car incorporating such an anti-theft system by opening a door of the car, applying considerable force to the car, or opening the trunk, the anti-theft system is actuated to cause a siren to blow or the headlamps to be turned on and off, thereby obstructing the attempted theft.
However, the alarm sounded by the siren or flashing of the headlamps is only effective if there are people nearby, and does not exhibit sufficient deterrent in deserted locations or at night. Therefore the applicant of the present invention has proposed a method of reporting the occurrence of abnormality to the driver by transmitting that fact to a remote control unit, which thereby sounds an alarm.
Even when the car is not actually being stolen, the remote control unit sometimes sounds the alarm because the shock sensor is actuated by force applied from the outside, because a noise sensor is actuated by excessive external noise, or for other reasons. On the other hand, when the car is actually being stolen, it is sometimes dangerous for the owner to run to the car alone. In such a case, the owner will want to ascertain the state of the anti-theft system before running to the car when he receives the alarm from the remote control unit, but no method of ascertaining the state of the car secretly at a place remote from the car has heretofore been known.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a method of ascertaining at a place remote from a car (e.g., at home) whether the car is actually being stolen or not before running to the car at the time of the occurrence of abnormality.
It is another object of the present invention to provide a method of ascertaining the state of a car by monitoring the sound within the car.
To achieve this aim, a method of monitoring the sound within a car according to the present invention adopts an anti-theft system and a mobile telephone system having the following structure.
Referring to FIG. 1, which is a block diagram of a system to which a method of monitoring the sound within a car according to the present invention is applied, the symbol MTS denotes a mobile telephone system and MSP an anti-theft system.
The mobile telephone system MTS includes a control unit 101, a transceiver unit 102, a T-connector 103 and an antenna 104.
The control unit 101 includes a control portion 101a, a microphone 101b, a speaker 101c, an operation and display portion 101d, and so forth.
The anti-theft system MSP includes a main body 201 which is composed of a sensor portion 201a for detecting abnormality suggestive of theft, an operation portion having a keyboard structure, a control portion having a micro computer structure, etc., and a remote control unit 202, known as a "pager", which externally turns on and off the anti-theft function and outputs an alarm indicating the occurrence of something unusual.
The control unit 101 and the transceiver unit 102 are connected such as to allow communication between the two by a plurality of power source control lines, digital data transmission/reception lines, sound lines and the like. Several necessary lines are selected from them and are connected to the main body 201 of the anti-theft system MSP through the T-connector 103.
When the driver leaves the car, the anti-theft system MSP is actuated and and the power of the mobile telephone system MTS is turned off.
If the anti-theft system MSP detects something unusual relating to possible theft in this state, the main body 201 of the anti-theft system transmits that fact to the remote control unit 202 and at the same time turns on the power of the mobile telephone system MTS 50 as to render it capable of receiving external calls.
When the remote control unit 202 receives the information as to the occurrence of something unsual and sounds the alarm by means of a buzzer or the like, whereby the owner of the car is made aware of the fact that something unusual has occurred with his car.
Even when the car is not actually being stolen, the remote control unit sometimes sounds the alarm because the shock sensor is actuated by force applied from the outside, or because a noise sensor is actuated by excessive external noise. When the car is actually being stolen, it is dangerous for the owner to run to the car alone. If the owner wants to ascertain the state of the anti-theft system before running to the car in such a case, the mobile telephone system MTS is called from an external telephone and a predetermined code for monitoring the sound within the car is input.
When the mobile telephone system MTS receives the code for monitoring the sound within the car, it transmits the sound within the car which is collected by the microphone 101b transmits from the antenna 104 through the transmission portion of the transceiver unit 102. In this way, it is possible to monitor the sound within the car and thereby ascertain the state of the car at a place remote from the car.
The above and other objects, features and advantages of the present invention will become clear from the following description of the preferred embodiment thereof, taken in conjunction with the accompanying drawings.